The present invention pertains to a dental post for retaining a dental restoration onto a tooth stub and to a method for making dental posts.
In dental practice, it has been well known to utilize a dental post for retaining a dental restoration or prosthetic structure which is built onto the tooth stub of the broken tooth. Normally, the tooth stub is prepared by cutting it down and drilling in it a bore into which a dental post is inserted. The dental post which is retained in the bore by suitable dental cement is received in the bore so that its cylindrical body substantially fills the bore while its head portion extends upwardly from the surface of the tooth stub. Then, a dental core is formed on the head portion of the dental post, and the dental restoration is built up on the dental core.
Dental posts known in the art are provided with various means which aid in retention of the dental posts within the bores of the tooth stubs. On some posts, there has been provided an external thread which forms an additional surface area to retain cement. The external thread may be a spiral thread formed about the periphery of the substantially cylindrical body portion of the dental post. Retention means on the dental post may be also formed by helical flutes or grooves of a large pitch. The multiple helical grooves also provide an increased surface for the cement to enter and thus a better retention of the dental post in the bore of the tooth stub.
U.S. Pat. No. 2,536,669 discloses a dental post on the shank and the head of which are provided inclined grooves. The grooves are inclined in two opposite directions with respect to the longitudinal axis of the shank.
While prior art dental posts with different retention grooves as described hereinabove have generally been quite useful, there has been a need to provide dental posts with more substantial retention means which would further prevent accidental pulling or rotating out of the dental post after setting in the cement.